DIY starter rebuild

Is there a starter rebuild kit for our motors? Has anyone here done it and is it worth doing? I only get 1-1.5 years from a starter and am tired of buying new ones. I want a high torque unit but don't have $450 to put in one right now.

What does it take to rebuild a starter? My starter just went and I have the time to rebuild it and wouldn't mind saving some coin. Can someone shine some light? What does it take? Are there any special tools required?

Doesn't the 6liter starter interchange, smaller, faster, and more torque.
What does one of those cost.
Id just get a lifetime starter. Only took me 15 min to change in the parts store parking lot.
(I just beat the old one with a bar until the truck started and then never shut it off until I had the new one)